Method of fabrication of prestressed metal panels

ABSTRACT

A METHOD OF FABRICATION OF PRESTRESSED METAL PANELS CONSISTING IN THAT THE METAL FRAMEWORK OF THE PANEL IS BUILT UP OF AT LEAST TWO SECTIONS JOINTED SO THAT ONE SECTION CAN BE TURNED WITH RELATION TO THE OTHER, ONE END OF THE SKIN IS FASTENED TO THE TURNING SECTION OF THE FRAMEWORK SET AT AN ANGLE TO THE OTHER SECTION WHILE ITS OTHER END IS FASTENED TO THE OPPOSITE EDGE OF THE OTHER SECTION OF THE FRAMEWORK   AFTER WHICH THE TURNING SECTION IS TURNED ATOUND THE POINT OF CONTACT BETWEEN THE FRAMEWORK SECTIONS UNTIL THEIR BUTT ENDS ARE ALIGNED AND BOTH SECTIONS OF THE FRAMEWORK ARE FASTENED TOGETHER.

June 15, 1971 v, ov ETAL 3,584,136

METHOD OF FABRICATION OF PRESTRESSED METAL PANELS Filed April 23 1969 5 13 1: fij/ fi/ vfl/g Q I I I 7 FIG. 4

United States Patent 3,584,360 METHOD OF FABRICATION OF PRESTRESSED METAL PANELS Viktor Ivanovich Trofimov, Zoologicheskaya ulitsa 30,

kv. 68, and Gennady Grigorievich Mikhailov, Bolotnikovskaya ulitsa 24, korpus 7, kv. 65, both of Moscow, U.S.S.R.

Filed Apr. 23, 1969, Ser. No. 818,612 Int. Cl. B23p 11/02, 17/00 US. Cl. 29-155 1 Claim ABSTRACT OF THE DISCLOSURE A method of fabrication of prestressed metal panels consisting in that the metal framework of the panel is built up of at least two sections jointed so that one section can be turned with relation to the other; one end of the skin is fastened to the turning section of the framework set at an angle to the other section while its other end is fastened to the opposite edge of the other section of the framework after which the turning section is turned around the point of contact between the framework sections until their butt ends are aligned and both sections of the framework are fastened together.

The present invention relates to methods of fabrication structural elements and more particularly it relates to methods of fabricating prestressed metal panels.

Known in the art is a method of fabricating prestressed metal panels which comprise a framework made of two fiat frames with a skin fastened to each of them, said method consisting in prestressing the panels by bending the frames in the opposite directions, then fastening the skins to the concave surface of the frames, straightening the frames and connecting them to each other. The skins are thus stressed.

The technology of manufacturing the prestressed metal panels in accordance with the known method is rather complicated. Bending of the frames, fixing them in the bent state and subsequent straightening call for a specialized equipment. Special appliances are also required to ensure stability of the frames in the process of bending. The process of fastening the skins to the bent frames is also complicated and labour consuming.

Therefore, fabrication of panels by the above-mentioned method can be carried out only in special factory shops with large production floor areas and a high headroom. In fabricating panels longer than 12 or 15 m. the technological difficulties are still more aggravated so that the above method of panel fabrication becomes altogether impracticable.

Besides, in the panels fabricated by the above method both sides of the skin have to be stressed.

It is an object of the present invention to eliminate the above disadvantages.

It is a further and more specific object of the invention to provide simpler method of fabricating prestressed metal panels which would not involve the use of specialized equipment and appliances and would allow only one of the skins to be stressed.

These objects have been accomplished by providing a method of fabricating the prestressed metal panels said panels consisting of a framework and at least one prestressed skin on one of the framework sides; according to the invention, for prestressing the skin, the framework is built-up of at least two sections installed with a provision for turning with relation to each other; one end of the skin is fastened to the turning section of the framework which is set at an angle to the other part at a certain distance from the point of contact between these two sections of 3,584,360 Patented June 15, 1971 the framework while the other end of the skin is fastened to the opposite section of the framework; then the turning section of the framework is turned around the point of contact between the framework sections until their butt ends coincide after which both sections of the framework are fastened together. Fabrication of panels, in accordance with the proposed method, is so simple that it can be carried out even on a building site, the length of the fabricated panels being practically unlimited.

Given below is a detailed description of the invention by way of example with reference to the accompanying drawings in which:

FIG. 1 illustrates a prestressed metal panel, side view;

'FI'G. 2same, partly cutaway view;

FIG. 3-main part of the framework and turning sections with fastened skin.

FIG. 4same, with the turning section set at an angle.

The metal panel consists of the skins 1 (FIGS. 1 and 2) and 2, and a framework. The framework consists of a main section 3 and turning sections 4 and 5. The main section 3 of the framework is formed by flat frames '6 and 7 interconnected by a trellis 8. The frame 6 is made shorter by the length of the turning sections 4 and 5 of the framework. The turning sections 4 and 5 of the frame work are made in the form of flat frames for better stiffness.

The skin 2 is secured to the frame 7 of the framework main section 3 without prestressing.

The skin 1 (FIG. 3) is fastened to the turning sections 4 and 5 of the framework at a certain distance 1 (FIG. 2) from the point where the framework turning sections 4 and 5 join the frame 6. The distance A (FIG. 3) between the turning sections 4 and 5 after the fastening of the skin 1 should be smaller than the length B of the frame 6 by the value Al which is determined analytically, to suit the required stressing of the skin 1.

If the distance A between the turning sections 4 and 5 is equal to the length B of the frame 6, the length Al is set by putting a pack of shims between the ends of the frame and the turning sections (the shims are not shown on the drawing).

To stress the skin 1 the turning section 5 (FIG. 4) of the framework is fastened to the main section 3 of the framework by the trellis 8. The turning section 4- of the framework is set at an angle of oz owing to the difference of the length Al.

The skin 1 is stressed by turning the inclined section 4 of the framework around the point C (the point of contact between said turning section and the frame '6 of the main section 3 of the framework) until the turning section 4 of the framework comes to the normal position in the panel, i.e. when the butt end of the turning section 4 is aligned with that of the frame 6 of the main section of the framework. In this position the turning section 4 is fastened to the main section 4 of the framework by the trellis 8 and the tensioned skin 1 is secured to the frame 6 by riveting, spot welding or other known methods.

Said turning may be performed manually, by winches or any other known methods, the maxiumum value of the turning force and ange oz being dependent on the required tensioning of the skin, and being adjustable by changing the distance 1 between the point where the skin is fastened to the turning section and the point of turning (point C).

This method can also be adapted for stressing both skins. In such a case both frames should have turning sections. Tensioning is carried out successively, i.e. at first one skin is tensioned than the other.

In an experimental specimen of a prestressed aluminium-alloy panel 3 m. wide and 12 m. long the tensile stresses in the skin have reached 610 kg./cm. being obtained within 3 minutes by 5 operators.

We claim:

1. A method of fabrication of prestressed metal panels comprising a framework and a skin located on at least one side of said framework wherein for tensioning the skin the framework is built up of at least two sections installed so that one section can turn with relation to the other; one end of said skin is fastened to the turning section of the framework which is set at an angle to the other section of the framework; this end of the skin is fastened at a certain distance from the point of contact between said framework sections while the other end is fastened to the opposite end of said other section of the framework; then said turning section of the framework is turned around the point of contact between said sections until 4 their butt ends are aligned, after which both parts of the framework are fastened together.

References Cited UNITED STATES PATENTS 2,110,752 3/1938 Wright 29-443 2,364,494 12/ 1944 Upson 29449 2,382,356 8/1945 Watter 29-449 2,662,272 12/1953 Macomber 29l55 0 THOMAS H. EAGER, Primary Examiner US. Cl. X.R. 29448 

